The old ways of doing business are changing. People are evolving and the way they want to do business is evolving, too. While you may not love every aspect of doing business, you absolutely need to love what you do overall.

“Turn your passion into profit,” is a marketing slogan that’s becoming a way of life for many entrepreneurs. James Altucher says it well in his book, Choose Yourself, “You can’t buy happiness with the currency of unhappiness.” Working at something you hate might make you some money, but it’s not going to lead you to true wealth.

With Valentine’s Day on many shelves and commercials right now, it’s a good time to talk about three entrepreneurs who turned what they love into successful empires.

Oprah: Even when Oprah had a successful talk show, she still knew there was more. She took her passion for spiritual work, reading (Oprah’s Book Club) and mentoring mainstream and transformed her show. She went from just a nationally syndicated daytime talk show to a global sensation and the go-to authority for inspiration.

One thing I really like about Oprah as a love what you do leader is that she pays it forward. She’s been responsible for the tipping points in many other successful entrepreneurs' careers. Think of Sara Blakely with Oprah’s endorsement of Spanx and the launch of the TV careers of Dr. Oz and Dr. Phil.

She says her personal creed is, “What you put out comes back all the time, no matter what.” Oprah is a shining example that doing what you love and helping others pays off.

What burning desires do you have that could translate into a passionate career? How can you help others with your leadership?

Jerry Seinfeld: Struggling actor and comedian stories are a dime a dozen. What makes Jerry Seinfeld’s unique is the enduring nature of his popular show, Seinfeld. He parlayed a comedy career into a show that ran for nearly 10 years (’89 to ’98) and is still in reruns today, more than 15 years after the final episode aired.

What made this popular “show about nothing” so successful when so many shows do not endure the test of time? It was likely Seinfeld’s commitment to a daily practice. In a Reddit “Ask Me Anything” topic thread this month, Jerry said, “Writer’s block is a phony, made up, BS excuse for not doing your work.”

Doing what you love means following through with action. Seinfeld made a habit out of writing and working on his comedy every day. A practice he referred to as not breaking the chain (each day is a link in the chain). He loves what he does and with constant application, he made a massive career out of that passion.

Do you have a daily practice that backs up your labor of love with actions?

Sir Richard Branson. You know Branson for his larger-than-life projects and massive PR stunts, but the Virgin Group founder got his start from his passion to innovate. Before the island in the Caribbean, the airline fleet and the mobile carrier division, there was his foray into mail-order records.

A love for music and a passion for improving things that frustrated him compelled Sir Richard to start his own record business. It was his idea to cut out the large retailers to offer records for less by delivery order, instead of browsing and buying in a store. That passion for innovation dictated every other move in Branson’s life.

“My interest in life comes from setting myself huge, apparently unachievable challenges and trying to rise above them,” he explains. And he has certainly achieved great heights, likely beyond most of his own expectations.

How do you rise above the bar you set for yourself? How do you find joy in overcoming challenges?